Turmeric and Curcumin

Safety and precautions

Curcumin is generally regarded as safe by the US Food and Drug Administration (FDA). Medical supervision is recommended with doses higher than those typically found in foods.

Epidemiological evidence and several clinical trials have found minimal side effects with oral curcumin up to 12 grams per day over several months.¹Lao CD, Rufin MT et al. Dose escalation of a curcuminoid formulation. BMC Complementary and Alternative Medicine 2006;6:10. Short-term intravenous use of liposomalvery tiny, fat-like particles used as delivery enhancers for some vitamins, minerals, and micronutrients to improve transport into the bloodstream curcumin appears to be safe up to a dose of 120 mg/m². Changes in red blood cells may indicate toxicity at higher doses.²Storka A, Vcelar B et al. Safety, tolerability and pharmacokinetics of liposomal curcumin in healthy humans. International Journal of Clinical Pharmacology and Therapeutics. 2015 Jan;53(1):54-65.

8 grams per day may produce toxicity during gemcitabine treatment, although evidence so far is conflicting:

• Low compliance due to intractable abdominal fullness or pain among people with advanced pancreatic cancer with 8 g oral curcumin daily, concurrently with gemcitabine 1,000 mg/m(2) IV weekly × 3 of 4 weeks in a small uncontrolled triala study in which a therapy is used, but without a comparison group to judge outcomes against; an uncontrolled trial is considered a weak study design³Epelbaum R, Schaffer M, Vizel B, Badmaev V, Bar-Sela G. Curcumin and gemcitabine in patients with advanced pancreatic cancer. Nutrition and Cancer. 2010;62(8):1137-41. 
• 100% compliance and no withdrawals due to toxicity among people with gemcitabine-resistant pancreatic cancer taking 8 g oral curcumin daily in combination with gemcitabine-based chemotherapy in a small uncontrolled trial⁴Kanai M, Yoshimura K et al. A phase I/II study of gemcitabine-based chemotherapy plus curcumin for patients with gemcitabine-resistant pancreatic cancer. Cancer Chemotherapy and Pharmacology. 2011 Jul;68(1):157-64. 

Interactions with cancer treatments

Caution is needed if you are undergoing chemotherapy. Curcumin can interact with chemotherapy drugs such as cyclophosphamide, doxorubicin⁵Yeung KS, Gubili J, Mao JJ. Herb-drug interactions in cancer care. Oncology (Williston Park). 2018 Oct 15;32(10):516-20; Weil A. Curcumin or turmeric? Andrew Weil, MD. Viewed October 11, 2021. or camptothecin.⁶McKinney N. Naturopathic Oncology, 3rd Edition. Victoria, BC, Canada: Liaison Press. 2016. Research gives more guidance on safe use with paclitaxel or irinotecan:

• A 21-day concomitant administration of 2 g turmeric per day during paclitaxel treatment showed only small changes in pharmacokinetic parameters that the researchers concluded are not clinically relevant.⁷Kalluru H, Mallayasamy SR, Kondaveeti SS, Chandrasekhar V, Kalachaveedu M. Effect of turmeric supplementation on the pharmacokinetics of paclitaxel in breast cancer patients: a study with population pharmacokinetics approach. Phytotherapy Research. 2022 Apr;36(4):1761-1769. 
• Administration of 4 g of a curcumin phosphatidylcholine complex (MTD) during irinotecan treatment did not significantly alter the plasma exposure and other PK properties of irinotecan and its metabolites, and there was no apparent increase in the incidence of irinotecan‐associated toxicities.⁸Gbolahan OB, O’Neil BH et al. A phase I evaluation of the effect of curcumin on dose-limiting toxicity and pharmacokinetics of irinotecan in participants with solid tumors. Clinical and Translational Science. 2022 May;15(5):1304-1315. 

If you are planning or undergoing chemotherapy, check with your oncology team about using curcumin or turmeric.

Preliminary evidence in humans shows that cucrumin may slightly reduce the effectiveness of tamoxifen. In a study of people with breast cancer, researchers gave tamoxifen with or without curcumin, 1200 mg three times a day. The group taking tamoxifen in combination with curcumin had about an 8% decrease in endoxifen levels. If the curcumin was compounded with piperine (often done to substantially improve curcumin absorption), endoxifen levels were further decreased, by 12%.⁹Hussaarts KGAM, Hurkmans DP et al. Impact of curcumin (with or without piperine) on the pharmacokinetics of tamoxifen. Cancers (Basel). 2019 Mar 22;11(3). pii: E403. Read more about this study and implications for use during tamoxifen treatment in the Expert commentary section in How do experts use turmeric and curcumin? ›

Side effects or adverse events

Side effects are mostly associated with doses higher than four grams per day,¹⁰Fadus MC, Lau C, Bikhchandani J, Lynch HT. Curcumin: an age-old anti-inflammatory and anti-neoplastic agent. Journal of Traditional and Complementary Medicine. 2016 Sep 9;7(3):339-346.  although oral curcumin up to 8 g (8,000 mg) per day for 3 months produced no toxicity among people with high risk of cancer or premalignant lesions.¹¹Cheng AL, Hsu CH et al. Phase I clinical trial of curcumin, a chemopreventive agent, in patients with high-risk or pre-malignant lesions. Anticancer Research. 2001 Jul-Aug;21(4B):2895-900. Side effects include these:

• Mild and self-resolving gastrointestinal disturbances such as loose stools, reflux, bloating, and abdominal discomfort
• Decreased iron levels
• Temporary rise in liver enzymes
• Suppressed platelet aggregation, possibly leading to bleeding
• Contact dermatitis, hives (urticaria)

In rare cases, extended use can cause stomach upset or heartburn¹²Weil A. Curcumin or turmeric? Andrew Weil, MD. Viewed October 11, 2021. or even liver damage.¹³Cooperman T. Turmeric and Curcumin Supplements and Spices Review. ConsumerLab.com. Viewed December 5, 2023.

Interactions with other therapies

Curcumin may inhibit platelets in the blood and increase the risk of bleeding caused by other drugs, such as aspirin, anticoagulants, antiplatelet drugs, and nonsteroidal anti-inflammatory drugs.¹⁴Shah BH, Nawaz Z et al. Inhibitory effect of curcumin, a food spice from turmeric, on platelet-activating factor- and arachidonic acid-mediated platelet aggregation through inhibition of thromboxane formation and Ca2+ signaling. Biochemical Pharmacology. 1999 Oct 1;58(7):1167-72.

The TRC Natural Medicines database lists several interactions with diabetes medications and other drugs that lower blood sugar, estrogens, drugs that slow blood clotting, and other drugs.

Curcumin can interfere with certain liver detoxification enzymes and interact with substrates of drugs.¹⁵Fadus MC, Lau C, Bikhchandani J, Lynch HT. Curcumin: an age-old anti-inflammatory and anti-neoplastic agent. Journal of Traditional and Complementary Medicine. 2016 Sep 9;7(3):339-346.

Piperine, which is often taken with curcumin, can slow the elimination of some prescription drugs including phenytoin (Dilantin), propranolol (Inderal), and theophylline.¹⁶Weil A. Curcumin or turmeric? Andrew Weil, MD. Viewed October 11, 2021.

Do not use (contraindications)

Stop use before surgery, as curcumin can increase bleeding. 

Compounds in curcumin can bind to iron and reduce iron’s availability, a concern to people with anemia or iron-storage problems. Iron levels may need to be monitored with curcumin supplement use, even among those with subclinical anemia or iron deficiency. Curcumin should therefore be taken with caution among those with marginally low iron stores or other diseases associated with iron such as anemia or chronic disease. Similarly, curcumin may possibly contribute to iron chelation, with the potential to cause a clinical or subclinical iron deficiency anemia.¹⁷ConsumerLab.com Answers. Is it true that taking turmeric/curcumin with food can reduce iron absorption from food? July 25, 2017. Viewed October 11, 2021; Fadus MC, Lau C, Bikhchandani J, Lynch HT. Curcumin: an age-old anti-inflammatory and anti-neoplastic agent. Journal of Traditional and Complementary Medicine. 2016 Sep 9;7(3):339-346.

Curcumin has antiplatelet properties, possibly increasing the risk of bleeding among people taking anti-clotting drugs.¹⁸Fadus MC, Lau C, Bikhchandani J, Lynch HT. Curcumin: an age-old anti-inflammatory and anti-neoplastic agent. Journal of Traditional and Complementary Medicine. 2016 Sep 9;7(3):339-346.

Cautions from integrative oncologist experts:¹⁹Weil A. Curcumin or turmeric? Andrew Weil, MD. Viewed October 11, 2021; Alschuler LN, Gazella KA. The Definitive Guide to Cancer, 3rd Edition: An Integrative Approach to Prevention, Treatment, and Healing. Berkeley, California: Celestial Arts. 2010; McKinney N. Naturopathic Oncology, 3rd Edition. Victoria, BC, Canada: Liaison Press. 2016.

Don’t use turmeric if you have gallstones, bile duct dysfunction (including biliary obstruction), hyperacidity, or stomach ulcers.

Pregnant or lactating women shouldn’t use turmeric supplements without their doctors’ approval. Curcumin should not be taken with these drugs:

• Anastrozole
• Cyclophosphamide
• Erlotinib

• Exemestane
• Letrozole
• Warfarin in therapeutic doses